1. Field of the Invention
The present invention relates to a method and apparatus for setting a sample observation condition, and a method and apparatus for sample observation, and more particularly, to a method and apparatus suitable for observing and measuring dimensions of a minute part, for example, a semiconductor device.
2. Background Art
Semiconductor devices in recent years have processing accuracies of 0.1 μm or less, and perform shape observation and dimensional control using a charged particle apparatus (mainly scanning electron microscope) in dimensional control for performance evaluation.
In samples for those latest semiconductor devices, when the shape and size of a pattern with a high aspect ratio (having long depth in the ratio of the pattern size and depth) such as a contact hole are observed and measured, a secondary electronic signal 2 generated by scanning of an electron beam 1 at the bottom of the pattern having a high aspect ratio as shown in FIG. 1 may be interrupted by the sidewall of the pattern and unable to reach the surface of the sample, making it impossible to obtain necessary information and realize shape observation and size measurement.
In order to solve such a problem, as shown in FIG. 2, for example, Patent Document 1 describes an art whereby a location to be evaluated is irradiated with an electron beam at a low accelerating voltage or a low magnification beforehand, the surface of the sample is (normally positively) charged (predosing), an electric field is formed between the bottom and the surface of the sample so that the secondary electronic signal 2 necessary for the shape observation and size measurement is made to reach the surface of the sample for detection.
[Patent Document 1] JP Patent Publication (Kokai) No. 2005-61998